EP0165842B1 - Production method for a multipoint light guide - Google Patents

Production method for a multipoint light guide Download PDF

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Publication number
EP0165842B1
EP0165842B1 EP85400966A EP85400966A EP0165842B1 EP 0165842 B1 EP0165842 B1 EP 0165842B1 EP 85400966 A EP85400966 A EP 85400966A EP 85400966 A EP85400966 A EP 85400966A EP 0165842 B1 EP0165842 B1 EP 0165842B1
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EP
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Prior art keywords
bundle
optical
process according
mould
optical fibers
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EP85400966A
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German (de)
French (fr)
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EP0165842A1 (en
Inventor
Jean Calvet
Jean-Claude Cavan
Jean-Claude Thevenin
Alain Fievet
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Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
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Commissariat a lEnergie Atomique CEA
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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/04—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings formed by bundles of fibres
    • G02B6/06—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings formed by bundles of fibres the relative position of the fibres being the same at both ends, e.g. for transporting images
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/0018—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 with means for preventing ghost images
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/02—Optical fibres with cladding with or without a coating
    • G02B6/02042—Multicore optical fibres

Definitions

  • the subject of the present invention is a method for making a multipoint light pipe and in particular making it possible to give it a particular shape.
  • the multipoint light pipes considered consist of bundles of ordered optical fibers. They are mainly used for the transport of images, each optical fiber transporting an elementary point of these images.
  • bundles of ordered fibers have many applications.
  • they can be used in the field of medicine and in particular for endoscopy, associated with an input optic.
  • They can also be used in the fields of electronics and visualization and in particular in the form of optical coupling wafers used for example for the corrections of curvature of images in order to obtain a plane image from a screen. cathodic or to ensure the connection between a plane phosphorescent screen and the curved photocathode of an image amplifier.
  • multipoint light pipes can, depending on their shape, in addition to the transport of images, be used for enlarging or reducing images.
  • image reducers or enlargers made up of ordered optical fibers having the shape of a conical beam whose inlet diameter and outlet diameter characterize the enlargement or reduction of these devices.
  • multipoint light pipes are generally made with glass or silica optical fibers, materials with good optical transmission characteristics (transparency).
  • these optical fibers have the disadvantage of being expensive, heavy and relatively inflexible.
  • the subject of the present invention is precisely a method for producing multipoint light pipes making it possible to remedy the various drawbacks given above. It makes it possible in particular to produce light pipes in a simple and inexpensive manner which can be used, in addition to image transport, for enlarging or reducing images.
  • the method for manufacturing a multipoint light pipe is characterized in that a bundle of plastic optical fibers, parallel to one another and adjacent, each comprising a bundle of optical fibers made of plastic a core and an optical sheath, each of these fibers having been produced beforehand by a drawing operation and having the ability to grow in diameter under the effect of heating, and the temperature of the assembly is raised homogeneously mold-bundle in order to increase the diameter of the optical fibers until these fibers fill the entire interior of the mold, the bundle of fibers thus treated forming the multipoint light pipe.
  • the process of the invention is based on one of the physical properties of certain optical fibers made of plastic, the manufacturing process of which comprises a drawing operation, fibers obtained by drawing from a preform for example.
  • plastics are not products with a clear melting point and their viscosity varies according to a wide temperature range.
  • the molecular structure of the plastics upon cooling, freezes in a drawn structure. This effect can be more or less accentuated depending on the conditions of manufacture of the optical fibers and in particular of the lowest drawing temperature used.
  • This stretched molecular structure makes it possible to give optical fibers mechanical properties and in particular flexibility properties.
  • optical fibers made of plastic having the ability to grow in diameter when heated, mention may in particular be made of optical fibers comprising an optical sheath of polyvinyl acetate and a core of polystyrene. These optical fibers can be obtained by drawing at relatively high temperatures and in particular close to 190 ° C.
  • the optical fibers used can be devoid of mechanical protection sheath.
  • the method of the invention may comprise an additional step consisting in demolding the bundle of plastic optical fibers obtained after the step of temperature rise.
  • a mold comprising a recess of cylindrical shape having a variable diameter and in particular a mold comprising a recess having a frustoconical part.
  • the various multipoint light pipes mentioned above may have fluorescent or scintillating properties.
  • plastic optical fibers are used, the core material of which contains scintillating or fluorescent doping products.
  • Such light pipes can in particular be used for the detection and / or localization of particles.
  • FIG. 1 schematically represents a multipoint light pipe obtained according to the method of the invention used both for transporting images and for enlarging or reducing images, and
  • FIG. 2 schematically represents a multipoint light pipe obtained according to the method of the invention having the shape of a "fly eye”.
  • the method of manufacturing a light pipe according to the invention consists first of all in using a bundle of ordered optical fibers made of plastic material obtained by drawing from a preform; these optical fibers are arranged parallel to one another and adjacent to one another.
  • optical fibers it is possible to use, for example, those described in the French patent application, cited above; these fibers include in particular an optical sheath made of polyvinyl acetate and a core of polystyrene.
  • optical fibers used are provided with a mechanical protective sheath, these can, according to the invention, be stripped over all or part of their length.
  • the bundle of fibers can be introduced into a mold. Then, according to the invention, the temperature of the mold-fiber bundle assembly is raised, in a homogeneous manner, in order to increase the diameter of the optical fibers until these fibers occupy all the volume offered to them. In particular, these heated optical fibers fill the entire interior of the mold and in particular the optical voids present at the start between the optical fibers of round shape, thus leading in most cases to obtaining a multipoint light pipe comprising hexagonal section optical fibers arranged in a honeycomb pattern.
  • optical fibers made of plastic comprising a polyvinyl acetate sheath and a polystyrene core obtained by drawing at a temperature of the order of 190 ° C.
  • filling the entire mold and obtaining the hexagonal shape optical fibers can be obtained by raising the temperature, homogeneously, to approximately 130-14 ⁇ ° C.
  • the rise in temperature can be done using a device of conventional type (oven for example) by direct heating of the mold containing the optical fibers.
  • the next step in the process of the invention consists in demolding the multipoint light pipe obtained.
  • the method of the invention makes it possible to obtain multipoint light conduits used for transporting images and having a magnification one; this can be achieved by using a tubular mold, that is to say a mold having a cylindrical recess having a constant diameter.
  • the invention it is possible to cut off the multipoint light pipe obtained in a direction perpendicular to the bundle of fibers constituting this pipe so as to form thin optical coupling wafers which can be used in the field of electronics and visualization.
  • the method according to the invention can also make it possible to produce image reducers or enlargers. This can be obtained by using a mold comprising a cylindrical recess having a variable diameter, and in particular a frustoconical recess, taking into account the fact that the heated plastic optical fibers can fill all the space which is offered to them. by a diameter expansion of these fibers.
  • the swelling of plastic optical fibers in diameter is limited.
  • optical fibers comprising a polyvinyl acetate sheath and a polystyrene core obtained by stretching at 190 ° C.
  • this swelling of the fibers is accompanied by a shortening in length proportional to the swelling; for a diametrical swelling by a factor of three, a shortening by a factor of nine is obtained.
  • the general reference light pipe 1 comprises a cylindrical part 2 of constant diameter, allowing the transport of images with a magnification one, and a frustoconical part 4, integral with the part 2, allowing the enlargement or reduction of images .
  • the plastic optical fibers 6, comprising a core 6a and an optical sheath 6b, constituting this light pipe have a hexagonal shape 8 in honeycomb obtained in accordance with the method of the invention.
  • a "fly eye” that is to say a multipoint light pipe which comprises a cylindrical part 10 of constant diameter and a part 12 in the form of a hemisphere, having, like a "fly eye", facets 14 of hexagonal and contiguous shape.
  • This light pipe is formed of plastic optical fibers 16 having a core 16a and an optical sheath 16b. It can be used for rough observation of the movements of a light source in a solid angle of 2 ⁇ , or for lighting in a solid angle of 2 ⁇ , from a light source emitting in the axis of the beam of cylindrical fibers, from a laser source for example.
  • multipoint light conduits of any shape, having luminescent or fluorescent properties.
  • plastic optical fibers are used, the core material of which contains fluorescent or scintillating doping elements such as for example the compound known under the abbreviation of butyl-PBD or that known under the abbreviation dimethyl-POPOP such as described in the French patent application cited above.
  • the light pipes can in particular be used for the detection and / or localization of particles.
  • the method of the invention makes it possible to obtain multipoint light conduits of all possible shapes and imaginable by simple swelling of optical fibers of plastic material in a predetermined volume, thanks to a heating step and this, without compacting said fibers as in the processes of the prior art.
  • This method has the advantage of simple and costly implementation, unlike certain methods of the prior art.

Description

La présente invention a pour objet un procédé permettant de réaliser un conduit de lumière multipoints et permettant notamment de lui donner une forme particulière.The subject of the present invention is a method for making a multipoint light pipe and in particular making it possible to give it a particular shape.

Les conduits de lumière multipoints considérés sont constitués de faisceaux de fibres optiques ordonnées. Ils sont principalement utilisés pour le transport d'images, chaque fibre optique transportant un point élémentaire de ces images.The multipoint light pipes considered consist of bundles of ordered optical fibers. They are mainly used for the transport of images, each optical fiber transporting an elementary point of these images.

Ces faisceaux de fibres ordonnées présentent de nombreuses applications. En particulier, ils peuvent être utilisés dans le domaine de la médecine et notamment pour l'endoscopie, associés avec une optique d'entrée. Ils peuvent aussi être utilisés dans les domaines de l'électronique et de la visualisation et notamment sous la forme de galettes de couplage optique utilisées par exemple pour les corrections de courbure d'images afin d'obtenir une image plane à partir d'un écran cathodique ou pour assurer la liaison entre un écran phosphorescent plan et la photocathode courbe d'un amplificateur d'images.These bundles of ordered fibers have many applications. In particular, they can be used in the field of medicine and in particular for endoscopy, associated with an input optic. They can also be used in the fields of electronics and visualization and in particular in the form of optical coupling wafers used for example for the corrections of curvature of images in order to obtain a plane image from a screen. cathodic or to ensure the connection between a plane phosphorescent screen and the curved photocathode of an image amplifier.

Ces conduits de lumière multipoints peuvent suivant leurs formes, outre le transport d'images, servir à l'agrandissement ou la réduction d'images. Sont connus, des réducteurs ou agrandisseurs d'images constitués de fibres optiques ordonnées présentant la forme d'un faisceau conique dont le diamètre d'entrée et le diamètre de sortie caractérisent le grandissement ou la réduction de ces dispositifs.These multipoint light pipes can, depending on their shape, in addition to the transport of images, be used for enlarging or reducing images. Are known, image reducers or enlargers made up of ordered optical fibers having the shape of a conical beam whose inlet diameter and outlet diameter characterize the enlargement or reduction of these devices.

Les différents types de conduits de lumière multipoints, décrits ci-dessus, sont généralement réalisés avec des fibres optiques en verre ou en silice, matériaux présentant de bonnes caractéristiques de transmission optique (transparence). En revanche, ces fibres optiques présentent l'inconvénient d'être chères, lourdes et relativement peu flexibles.The different types of multipoint light pipes, described above, are generally made with glass or silica optical fibers, materials with good optical transmission characteristics (transparency). However, these optical fibers have the disadvantage of being expensive, heavy and relatively inflexible.

Ces conduits de lumière connus en fibres de verre sont généralement réalisés soit directement par un assemblage de fibres optiques ordonnées suivi d'un compactage à chaud et sous pression, soit par un assemblage de faisceau élémentaires de fibres optiques obtenus par des étirages successifs.These known light pipes made of glass fibers are generally produced either directly by an assembly of ordered optical fibers followed by hot and pressure compacting, or by an assembly of elementary bundles of optical fibers obtained by successive drawing.

Ces procédés de fabrication de conduits de lumière présentent un certain nombre d'inconvénients et en particulier une mise en ceuvre relativement complexe et coûteuse. Par exemple, l'utilisation de fibres de verre implique une température de travail élevée, supérieure à 600°C; lors du compactage sous pression, entre les deux parties d'un moule, des difficultés apparaissent à la jonction entre ces deux parties; pour la fabrication de réducteurs d'images, on est contraint d'étirer un faisceau et de prélever un tronçon de cône d'étirage. Par ailleurs, ces procédés limitent considérablement les applications des conduites de lumière multipoints obtenus.These methods of manufacturing light pipes have a number of drawbacks and in particular a relatively complex and costly implementation. For example, the use of glass fibers implies a high working temperature, above 600 ° C; during compaction under pressure, between the two parts of a mold, difficulties appear at the junction between these two parts; for the production of image reducers, one is forced to stretch a beam and to take a stretch of stretching cone. Furthermore, these methods considerably limit the applications of the multipoint light pipes obtained.

Par ailleurs, il est connu du document «Patents Abstracts of Japan», vol. 7, n° 30, p. 173 (1175) 5 février 1983 une méthode de polissage de l'extrémité d'une fibre optique plastique obtenue par étirage et présentant la faculté de grossir en diamètre sous l'effet d'un chauffage. Cette méthode consiste à couper l'extrémité de la fibre et à approcher cette extrémité d'une source de chauffage. Ce chauffage engendre un gonflement diamétral de l'extrémité de la fibre et la libération des contraintes mécaniques introduites dans ladite extrémité lors de la coupe.Furthermore, it is known from the document “Patents Abstracts of Japan”, vol. 7, n ° 30, p. 173 (1175) 5 February 1983 a method of polishing the end of a plastic optical fiber obtained by stretching and having the ability to grow in diameter under the effect of heating. This method consists in cutting the end of the fiber and approaching this end to a heating source. This heating generates a diametrical swelling of the end of the fiber and the release of the mechanical stresses introduced into said end during cutting.

La présente invention a justement pour objet un procédé de réalisation de conduits de lumière multipoints permettant de remédier aux différents inconvénients donnés ci-dessus. Elle permet notamment de réaliser des conduits de lumière de façon simple et peu coûteuse pouvant servir, outre au transport d'images, à l'agrandissement ou à la réduction d'images.The subject of the present invention is precisely a method for producing multipoint light pipes making it possible to remedy the various drawbacks given above. It makes it possible in particular to produce light pipes in a simple and inexpensive manner which can be used, in addition to image transport, for enlarging or reducing images.

Selon l'invention, le procédé de fabrication d'un conduit de lumière multipoints se caractérise en ce que l'on dispose à l'intérieur d'un moule un faisceau de fibres optiques en matière plastique, parallèles entre elles et adjacentes, comprenant chacune un coeur et une gaine optique, chacune de ces fibres ayant été réalisé préalablement par une opération d'étirage et présentant la faculté de grossir en diamètre sous l'effet d'un chauffage, et que l'on élève la température de l'ensemble moule-faisceau de façon homogène afin d'augmenter le diamètre des fibres optiques jusqu'à ce que ces fibres remplissent tout l'intérieur du moule, le faisceau de fibres ainsi traité formant le conduit de lumière multipoints.According to the invention, the method for manufacturing a multipoint light pipe is characterized in that a bundle of plastic optical fibers, parallel to one another and adjacent, each comprising a bundle of optical fibers made of plastic a core and an optical sheath, each of these fibers having been produced beforehand by a drawing operation and having the ability to grow in diameter under the effect of heating, and the temperature of the assembly is raised homogeneously mold-bundle in order to increase the diameter of the optical fibers until these fibers fill the entire interior of the mold, the bundle of fibers thus treated forming the multipoint light pipe.

Le procédé de l'invention est basé sur l'une des propriétés physiques de certaines fibres optiques en matière plastique dont le procédé de fabrication comporte une opération d'étirage, des fibres obtenues par étirage à partir d'une préforme par exemple.The process of the invention is based on one of the physical properties of certain optical fibers made of plastic, the manufacturing process of which comprises a drawing operation, fibers obtained by drawing from a preform for example.

En effet, les matières plastiques ne sont pas des produits à point de fusion franc et leurs viscosité varie suivant une large gamme de température. En particulier, lors de l'étirage des matières plastiques constituant les fibres optiques, au cours de leurfabri- cation, la structure moléculaire des matières plastiques, lors du refroidissement, se fige dans une structure étirée. Cet effet peut être plus ou moins accentué suivant les conditions de fabrication des fibres optiques et en particulier de la température d'étirage la plus basse utilisée.In fact, plastics are not products with a clear melting point and their viscosity varies according to a wide temperature range. In particular, during the drawing of the plastics constituting the optical fibers, during their manufacture, the molecular structure of the plastics, upon cooling, freezes in a drawn structure. This effect can be more or less accentuated depending on the conditions of manufacture of the optical fibers and in particular of the lowest drawing temperature used.

Cette structure moléculaire étirée permet de donner aux fibres optiques propriétés mécaniques et notamment des propriétés de souplesse.This stretched molecular structure makes it possible to give optical fibers mechanical properties and in particular flexibility properties.

Les inventeurs ont mis en évidence le fait que cette structure moléculaire étirée a tendance à reprendre sa forme première (c'est-à-dire avant étirage), lors d'un chauffage suffisant des matières plastiques de ces fibres, entraînant un gonflement diamétral desdites fibres, lié à un raccourcissement de celles-ci. C'est cette propriété de certaines fibres optiques plastiques que l'on utilise dans l'invention.The inventors have demonstrated the fact that this stretched molecular structure tends to return to its original shape (that is to say before stretching), when the plastics of these fibers are heated sufficiently, causing said diameters to swell. fibers, linked to a shortening of these. It is this property of certain plastic optical fibers that is used in the invention.

Comme fibres optiques en matière plastique, présentant la faculté de grossir en diamètre lorsqu'on les chauffe, on peut notamment citer des fibres optiques comportant une gaine optique en polyacétate de vinyle et un coeur en polystyrène. Ces fibres optiques peuvent être obtenus par étirage à des températures relativement élevées et en particulier voisines de 190°C.As optical fibers made of plastic, having the ability to grow in diameter when heated, mention may in particular be made of optical fibers comprising an optical sheath of polyvinyl acetate and a core of polystyrene. These optical fibers can be obtained by drawing at relatively high temperatures and in particular close to 190 ° C.

De telles fibres optiques en matière plastique ainsi que leurs procédé de fabrication par étirage ont été décrits dans la demande de brevet français FR-A-2 533 709 déposée le 23 septembre 1982 au nom du demandeur.Such plastic optical fibers as well as their stretching manufacturing process have been described in French patent application FR-A-2 533 709 filed on September 23, 1982 in the name of the applicant.

Selon l'invention, les fibres optiques utilisées peuvent être dépourvues de gaine mécanique de protection.According to the invention, the optical fibers used can be devoid of mechanical protection sheath.

Par ailleurs, selon l'application envisagée, le procédé de l'invention peut comprendre une étape supplémentaire consistant à démouler le faisceau de fibres optiques plastiques obtenu après l'étape de montée en température.Furthermore, according to the application envisaged, the method of the invention may comprise an additional step consisting in demolding the bundle of plastic optical fibers obtained after the step of temperature rise.

Si l'on désire réaliser des galettes de couplage optique on peut, selon l'invention, après le démoulage du faisceau de fibres optiques traité, effectuer un tronçonnage de ce faisceau selon une direction perpendiculaire audit faisceau pour former les galettes.If it is desired to produce optical coupling wafers, it is possible, according to the invention, after demolding the bundle of treated optical fibers, cutting up this bundle in a direction perpendicular to said bundle to form the wafers.

Si l'on désire réaliser un conduit de lumière multipoints permettant le transport d'images selon un grandissement un, on peut, selon l'invention, utiliser un moule comportant un évidement de forme cylindrique ayant un diamètre constant.If it is desired to produce a multi-point light pipe allowing the transport of images at one magnification, it is possible, according to the invention, to use a mold comprising a recess of cylindrical shape having a constant diameter.

Si l'on désire réaliser des conduits de lumière multipoints permettant en plus du transport d'images, l'agrandissement ou la réduction d'images, on peut selon l'invention utiliser un moule comportant un évidement de forme cylindrique ayant un diamètre variable et notamment un moule comportant un évidement présentant une partie tronconique.If it is desired to produce multipoint light conduits allowing, in addition to image transport, enlargement or reduction of images, it is possible according to the invention to use a mold comprising a recess of cylindrical shape having a variable diameter and in particular a mold comprising a recess having a frustoconical part.

Selon l'invention, les différents conduits de lumière multipoints cités précédemment peuvent présenter des propriétés fluorescentes ou scintillantes.According to the invention, the various multipoint light pipes mentioned above may have fluorescent or scintillating properties.

A cet effet, on utilise des fibres optiques en matière plastique dont le matériau de coeur contient des produits dopants scintillants ou fluorescents. De tels conduits de lumière peuvent notamment être utilisés pour la détection et/ou la localisation de particules.To this end, plastic optical fibers are used, the core material of which contains scintillating or fluorescent doping products. Such light pipes can in particular be used for the detection and / or localization of particles.

D'autres caractéristiques et avantages de l'invention ressortiront mieux de la description qui va suivre, donnée à titre illustratif et non limitatif, en référence aux figures annexées dans lesquelles:Other characteristics and advantages of the invention will emerge more clearly from the description which follows, given by way of illustration and not limitation, with reference to the appended figures in which:

la figure 1 représente schématiquement un conduit de lumière multipoints obtenu selon le procédé de l'invention servant à la fois au transport d'images et au grandissement ou à la réduction d'images, etFIG. 1 schematically represents a multipoint light pipe obtained according to the method of the invention used both for transporting images and for enlarging or reducing images, and

la figure 2 représente schématiquement un conduit de lumière multipoints obtenu selon le procédé de l'invention présentant la forme d'un «oeil de mouche».FIG. 2 schematically represents a multipoint light pipe obtained according to the method of the invention having the shape of a "fly eye".

Le procédé de fabrication d'un conduit de lumière selon l'invention consiste tout d'abord à utiliser un faisceau de fibres optiques ordonnées en matière plastique obtenues par étirage à partir d'une préforme; ces fibres optiques sont disposées parallèlement entre elles et de façon adjacente. Comme fibres optiques on peut utiliser par exemple celles décrites dans la demande de brevet français, citée précédemment; ces fibres comprennent notamment une gaine optique réalisée en acétate de polyvinyle et un coeur en polystyrène.The method of manufacturing a light pipe according to the invention consists first of all in using a bundle of ordered optical fibers made of plastic material obtained by drawing from a preform; these optical fibers are arranged parallel to one another and adjacent to one another. As optical fibers, it is possible to use, for example, those described in the French patent application, cited above; these fibers include in particular an optical sheath made of polyvinyl acetate and a core of polystyrene.

Lorsque les fibres optiques utilisées sont munies d'une gaine mécanique de protection, celles-ci peuvent, selon l'invention, être dénudées sur toute ou partie de leur longueur.When the optical fibers used are provided with a mechanical protective sheath, these can, according to the invention, be stripped over all or part of their length.

Après ce dénudage des fibres optiques, le faisceau de fibres peut être introduit dans un moule. Ensuite, selon l'invention, on élève la température de l'ensemble moule-faisceau de fibres, de façon homogène, afin d'augmenter le diamètre des fibres optiques jusqu'à ce que ces fibres occupent tout le volume qui leur est offert. En particulier, ces fibres optiques chauffées remplissent tout l'intérieur du moule et notamment les vides optiques présents au départ entre les fibres optiques de forme ronde, conduisant ainsi dans la plupart des cas à l'obtention d'un conduit de lumière multipoints comportant des fibres optiques de section hexagonale disposées en nid d'abeille.After this stripping of the optical fibers, the bundle of fibers can be introduced into a mold. Then, according to the invention, the temperature of the mold-fiber bundle assembly is raised, in a homogeneous manner, in order to increase the diameter of the optical fibers until these fibers occupy all the volume offered to them. In particular, these heated optical fibers fill the entire interior of the mold and in particular the optical voids present at the start between the optical fibers of round shape, thus leading in most cases to obtaining a multipoint light pipe comprising hexagonal section optical fibers arranged in a honeycomb pattern.

Dans le cas des fibres optiques en matière plastique comportant une gaine en polyacétate de vinyle et un coeur en polystyrène obtenues par étirage à une température de l'ordre de 190°C, le remplissage de tout le moule et l'obtention de la forme hexagonale des fibres optiques peuvent être obtenus en élevant la température, de façon homogène, à environ 130- 14µ ° C.In the case of optical fibers made of plastic comprising a polyvinyl acetate sheath and a polystyrene core obtained by drawing at a temperature of the order of 190 ° C., filling the entire mold and obtaining the hexagonal shape optical fibers can be obtained by raising the temperature, homogeneously, to approximately 130-14 µ ° C.

L'élévation en température peut se faire à l'aide d'un appareil de type classique (four par exemple) par chauffage direct du moule contenant les fibres optiques.The rise in temperature can be done using a device of conventional type (oven for example) by direct heating of the mold containing the optical fibers.

L'étape suivante du procédé de l'invention consiste à réaliser un démoulage du conduit de lumière multipoints obtenu.The next step in the process of the invention consists in demolding the multipoint light pipe obtained.

Le procédé de l'invention permet d'obtenir des conduits de lumière multipoints servant au transport d'images et présentant un grandissement un; ceci peut être réalisé en utilisant un moule de forme tubulaire, c'est-à-dire un moule comportant un évidement de forme cylindrique ayant un diamètre constant.The method of the invention makes it possible to obtain multipoint light conduits used for transporting images and having a magnification one; this can be achieved by using a tubular mold, that is to say a mold having a cylindrical recess having a constant diameter.

Selon l'invention, il est possible de réaliser un tronçonnage du conduit de lumière multipoints obtenu selon une direction perpendiculaire au faisceau de fibres constituant ce conduit de façon à former des galettes de couplage optique de faible épaisseur pouvant être utilisées dans le domaine de l'électronique et de la visualisation.According to the invention, it is possible to cut off the multipoint light pipe obtained in a direction perpendicular to the bundle of fibers constituting this pipe so as to form thin optical coupling wafers which can be used in the field of electronics and visualization.

Le procédé selon l'invention peut aussi permettre de réaliser des réducteurs ou agrandisseurs d'images. Ceci peut être obtenu en utilisant un moule comportant un évidement de forme cylindrique ayant un diamètre variable, et en particulier un évidement de forme tronconique, compte tenu du fait que les fibres optiques en matière plastique chauffée peuvent remplir tout l'espace qui leur est offert par une dilatation en diamètre de ces fibres.The method according to the invention can also make it possible to produce image reducers or enlargers. This can be obtained by using a mold comprising a cylindrical recess having a variable diameter, and in particular a frustoconical recess, taking into account the fact that the heated plastic optical fibers can fill all the space which is offered to them. by a diameter expansion of these fibers.

Bien entendu, le gonflement des fibres optiques plastiques en diamètre est limité. Par exemple, dans le cas de fibres optiques comportant une gaine en polyacétate de vinyle et un coeur en polystyrène obtenus par étirage à 190°C, il est possible d'obtenir un accroissement des fibres en diamètre d'un facteur trois par un chauffage homogène vers 140°C. Il est à noter que ce gonflement des fibres s'accompagne d'un raccourcissement en longueur proportionnel au gonflement; pour un gonflement diamétral d'un facteur trois, on obtient un raccourcissement d'un facteur neuf.Of course, the swelling of plastic optical fibers in diameter is limited. For example, in the case of optical fibers comprising a polyvinyl acetate sheath and a polystyrene core obtained by stretching at 190 ° C., it is possible to obtain an increase in the fibers in diameter by a factor of three by uniform heating. around 140 ° C. It should be noted that this swelling of the fibers is accompanied by a shortening in length proportional to the swelling; for a diametrical swelling by a factor of three, a shortening by a factor of nine is obtained.

Du fait du principe même du procédé de l'invention, il est possible d'obtenir, comme représenté sur la figure 1, un conduit de lumière multipoints combinant à la fois un transport d'images avec un grandissement un ainsi qu'un agrandissement ou une réduction de ces images et ce sans interruption des fibres optiques. Le conduit de lumière de référence générale 1 comporte une partie cylindrique 2 de diamètre constant, permettant le transport d'images avec un grandissement un, et une partie tronconique 4, solidaire de la partie 2, permettant l'agrandissement ou la réduction d'images. Les fibres optiques plastiques 6, comportant un coeur 6a et une gaine optique 6b, constituant ce conduit de lumière présentent une forme hexagonale 8 en nid d'abeilles obtenue conformément au procédé de l'invention.Due to the very principle of the method of the invention, it is possible to obtain, as shown in FIG. 1, a multipoint light pipe combining both an image transport with a magnification and an enlargement or a reduction of these images without interrupting the fi optical berries. The general reference light pipe 1 comprises a cylindrical part 2 of constant diameter, allowing the transport of images with a magnification one, and a frustoconical part 4, integral with the part 2, allowing the enlargement or reduction of images . The plastic optical fibers 6, comprising a core 6a and an optical sheath 6b, constituting this light pipe have a hexagonal shape 8 in honeycomb obtained in accordance with the method of the invention.

Avec un moule comportant un évidement de forme cylindrique ayant un diamètre variable, il est aussi possible de réaliser, comme représenté sur la figure 2, un «oeil de mouche», c'est-à-dire un conduit de lumière multipoints qui comprend une partie cylindrique 10 de diamètre constant et une partie 12 en forme de demi-sphère, présentant, comme un «oeil de mouche», des facettes 14 de forme hexagonale et jointives. Ce conduit de lumière est formé de fibres optiques plastiques 16 ayant un coeur 16a et une gaine optique 16b. Il peut être utilisé pour l'observation grossière des déplacements d'une source lumineuse dans un angle solide de 2π, ou pour l'éclairage dans un angle solide de 2π, à partir d'une source lumineuse émettant dans l'axe du faisceau de fibres cylindrique, d'une source laser par exemple.With a mold having a cylindrical recess having a variable diameter, it is also possible to produce, as shown in FIG. 2, a "fly eye", that is to say a multipoint light pipe which comprises a cylindrical part 10 of constant diameter and a part 12 in the form of a hemisphere, having, like a "fly eye", facets 14 of hexagonal and contiguous shape. This light pipe is formed of plastic optical fibers 16 having a core 16a and an optical sheath 16b. It can be used for rough observation of the movements of a light source in a solid angle of 2π, or for lighting in a solid angle of 2π, from a light source emitting in the axis of the beam of cylindrical fibers, from a laser source for example.

Selon l'invention, il est aussi possible de réaliser des conduits de lumière multipoints, de forme quelconque, présentant des propriétés luminescentes ou fluorescentes. A cet effet, on utilise des fibres optiques en matière plastique dont le matériau de coeur contient des éléments dopants fluorescents ou scintillants comme par exemple le composé connu sous l'abréviation de butyl-PBD ou celui connu sous l'abréviation diméthyl-POPOP tels que décrit dans la demande de brevet français citée précédemment. Les conduits de lumière peuvent notamment être utilisés pour la détection et/ou localisation de particules.According to the invention, it is also possible to produce multipoint light conduits, of any shape, having luminescent or fluorescent properties. For this purpose, plastic optical fibers are used, the core material of which contains fluorescent or scintillating doping elements such as for example the compound known under the abbreviation of butyl-PBD or that known under the abbreviation dimethyl-POPOP such as described in the French patent application cited above. The light pipes can in particular be used for the detection and / or localization of particles.

Le procédé de l'invention permet d'obtenir des conduits de lumière multipoints de toutes les formes possibles et imaginables par simple gonflement de fibres optiques en matière plastique dans un volume prédéterminé, grâce à une étape de chauffage et ce, sans compactage desdites fibres comme dans les procédés de l'art antérieur. Ce procédé présente l'avantage d'une mise en oeuvre simple et peut coûteuse contrairement à certains procédés de l'art antérieur.The method of the invention makes it possible to obtain multipoint light conduits of all possible shapes and imaginable by simple swelling of optical fibers of plastic material in a predetermined volume, thanks to a heating step and this, without compacting said fibers as in the processes of the prior art. This method has the advantage of simple and costly implementation, unlike certain methods of the prior art.

On peut par exemple réaliser un conduit de lumière à plusieurs points alignés en introduisant un ruban formé de fibres juxtaposées selon une seule couche dans un moule à section rectangulaire et en élevant la température; dans ce cas, les fibres prennent une section carrée ou rectangulaire.One can for example make a light pipe at several aligned points by introducing a ribbon formed of fibers juxtaposed in a single layer in a mold with rectangular section and by raising the temperature; in this case, the fibers take a square or rectangular section.

Claims (9)

1. Process for the production of a multipoint light guide (1), characterized in that within a mould is arranged a bundle of optical fibres (6, 16) made from a plastics material, having a core (6a, 16a) and an optical sheat (6b, 16b), each of whose fibres (6, 16) has previously been produced by a drawing operation and being able to increase in diameter under the effect of heating, and in that the temperature of the mould-bundle assembly is homogeneously increased in order to increase the diameter of the optical fibres (6, 16) until they occupy the entire interior of the mould, the bundle of fibres treated in this way forming the multipoint light guide (1).
2. Production process according to claim 1, characterised in that the optical fibres (6, 16) do not have a mechanical covering.
3. Process according to either of the claims 1 and 2, characterized in that it comprises a supplementary stage of demoulding the treated bundle of optical fibres (6).
4. Process according to claim 3, characterized in that, following the demoulding of the treated bundle of optical fibres (6, 16), this bundle is cut in a direction perpendicular thereto, in order to form optical coupling wafers.
5. Process acording to any one of the claims 1 to 4, characterized in that the optical fibres (6, 16) have a polyvinyl acetate optical sheat (6b, 16b) and a polystyrene core (6a, 16a).
6. Process according to claim 5, characterized in that the fibre core contains scintillating or fluorescent doping products.
7. Process according to any one of the claims 1 to 6, characterized in that the mould has a cylindrical recess having a constant diameter.
8. Process according to any one of the claims 1 to 6, characterized in that the mould has a cylindrical recess with a variable diameter.
9. Process according to claim 8, characterized in that the mould has a recess with a frustum-shaped portion.
EP85400966A 1984-05-23 1985-05-15 Production method for a multipoint light guide Expired EP0165842B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8408058A FR2564983B1 (en) 1984-05-23 1984-05-23 PROCESS FOR PRODUCING A MULTI-POINT LIGHT DUCT AND PRODUCTS OBTAINED ACCORDING TO THIS PROCESS
FR8408058 1984-05-23

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EP0165842B1 true EP0165842B1 (en) 1988-03-09

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JP (1) JPS60257406A (en)
DE (1) DE3561847D1 (en)
FR (1) FR2564983B1 (en)
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Families Citing this family (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4806289A (en) * 1987-01-16 1989-02-21 The Dow Chemical Company Method of making a hollow light pipe
US4871487A (en) * 1987-01-16 1989-10-03 The Dow Chemical Company Method of making a polymeric optical waveguide by coextrusion
FR2609778B1 (en) * 1987-01-16 1989-03-31 Thomson Csf HIGH LUMINANCE COLD LIGHT SOURCE AND USE FOR AN IMAGE VIEWING DEVICE
FR2627867B1 (en) * 1988-02-26 1990-08-03 Baron Jackie Jean METHOD FOR MANUFACTURING AN OPTICAL FIBER LIGHT SENSOR PANEL OR SENSOR, AND PANEL OR SENSOR OBTAINED BY SAID METHOD
DE3806158A1 (en) * 1988-02-26 1988-12-22 Peter Dipl Phys Thebock Image-guiding (image-carrying, image transmission) optical system having a viewing angle of more than 270 degrees having an image evaluation system connected downstream
AT396183B (en) * 1988-06-28 1993-06-25 Hrabalek Ernst BRACKET FOR RECEIVING A FINAL SECTION OF A BUNCH OF PLASTIC LIGHT GUIDES
JPH0221619U (en) * 1988-07-27 1990-02-14
US4929048A (en) * 1988-11-10 1990-05-29 Fiberview Corporation Fiber optic display
US5077820A (en) * 1990-08-17 1991-12-31 Mitsubishi Rayon Company, Ltd. Optical fiber photoconductor having multi-filament type optical fiber units
DE4034058C1 (en) * 1990-10-26 1992-01-09 Heraeus Quarzglas Gmbh, 6450 Hanau, De
US5287424A (en) * 1992-07-06 1994-02-15 Sheem Sang K Optical fiber coupler with overlapping core-extensions, and manufacturing methods of the same
US5222180A (en) * 1992-10-29 1993-06-22 Hoechst Celanese Corp. Polymer optical fibre bundle and method of making same
DE4301477C1 (en) * 1993-01-21 1993-12-23 Deutsche Aerospace Optical fibre device for directional optical sensor head - uses parallel optical fibres with differently angled light reception end faces

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB924774A (en) * 1961-07-17 1963-05-01 Thomas Ballantyne Clerk Improvements in or relating to optical devices

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2132047A1 (en) * 1971-06-28 1973-01-11 Siemens Ag DEVICE FOR THE TRANSFER OF IMAGES OR THE LIKE
JPS5577704A (en) * 1979-10-26 1980-06-11 Toray Ind Inc Optical wire-form body
JPS57181510A (en) * 1981-04-30 1982-11-09 Mitsubishi Rayon Co Ltd Treatment of end of plastic optical fiber
JPS599202U (en) * 1982-07-08 1984-01-20 東芝機器株式会社 oil burning equipment
FR2533709B1 (en) * 1982-09-23 1985-10-18 Commissariat Energie Atomique OPTICAL FIBERS IN PLASTIC MATERIAL, ESPECIALLY SPARKLING AND THEIR MANUFACTURING METHOD
JPS5986003A (en) * 1982-11-09 1984-05-18 Mitsubishi Rayon Co Ltd Manufacture of synthetic resin body for transmitting image

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB924774A (en) * 1961-07-17 1963-05-01 Thomas Ballantyne Clerk Improvements in or relating to optical devices

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EP0165842A1 (en) 1985-12-27
FR2564983B1 (en) 1987-12-18
FR2564983A1 (en) 1985-11-29
US4668445A (en) 1987-05-26
JPS60257406A (en) 1985-12-19
NO852072L (en) 1985-11-25
DE3561847D1 (en) 1988-04-14

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